I've not done a Mill Creek, but for the canoe, skerry and SUP I've done so far, I wound up having to fill and fair in the bow and stern where the strakes meet on each one. I used the same kind of mix as the fillets.  I tried to use the alcohol rag/finger smoothing but always wind up doing some sanding to smooth it and round it off a bit.  Really sharp prows don't like to take the fiberglass cloth tightly.  Rounded off some, the cloth drapes better.  I still wound up cutting a slit in the cloth on my SUP to keep the cloth from lifting off.  I went back with a layer on the bow of bias-cut cloth about 4" wide to get it to cover the bow where I'd cut the slit in the hull glass.  I'm not the neatest epoxy user, but it worked out ok.  I envy some of the work I see in the pictures on here.

the mill creek is not a lapstrake design so in general you want to round these edges so the glass will easily lay over these 'corners'. 

the role of thickend epoxy on the outside is to fill any space that opens up on the seams so that when you glass over it, you don't have an air bubble or other hollow at the seam which significantly weakens the glass.

a long flexible sanding block (sometimes called a long board or faring board) is a great tool for rounded edge to get a uniform circumfrence on your rounded over edge.

you will still get a nice paneled look with this approach...particularly if you are careful to ensure your rounded over sanding is consistent (which is why i mentioned the flexible sanding block.

coming back to technique for filling in these gaps, i try to do a little pre-work to prevent the thickend epoxy from ending up all over the place.   so i put some blue tape on either side of the joint before i trowel the thickened epoxy into the joint just to keep the epoxy where i want it. once i am done, i pull the blue tape up and carefully clean up any other epoxy spills.  i let the epoxy set before i round my edges.  after the edges, i may come back with a little more to fill any gaps i might have missed.   

i hope this helps

h

i also wanted to mention another thread that may be relevant 'nubs on bilge and sheer panels Mill creek 13' and the discussion on that thread about beveling the panels.

if you beveled the panels so that there is no open joint between the them, there is very little need for filling the gap (in the seams) with thickened epoxy....as there will be little if any gap and you will get an edge between the panels that looks a bit sharper if that is your preference.   this also a preferred approach if you are trying to do a bright finished hull.  you will still need a little touch of rounding, but it can be quite minor as the angle between the panels in fairly oblique and the cloth should have no trouble staying down.

that said, the most important element to make it look good assuming you do want to round it and your going to paint it, is to have consistency so the edges of the rounded panels look fare and not wobbly.  the other advantage of a more rounded edge, fwiw, is that it is less easily damaged and dinged.   ad sharp edge is more subject to damage than an edge where any 'dinging' force gets more disipated.

anyway, i suggest you read that other thread as well.

h

   Thanks guys

@hspira I know it's not lapstrake in the true sense I just used that word to differentiate the objective of keeping the line  as to form a more two separate panel look as opposed to a more one flowing panel look.

been learning a lot from a video by Bill Thomas on offcenterharbor.com pt 11 on the build of a fox canoe very similar to the Mill Creek. Flat bottom,sheer panel,bilge panel open cockpit. Unfortunately the entire build is not shown so no filling or sanding techniques are seen but after that process he mentions not rounding the sheer/bilge seam and maintaining it as a fair line from one end to the other.

There's not a lot of edge there to maintain anyway especially fore and aft but I get what your saying in regard to staying consistent with the use of the longboard. I think at this point I've got enough education to go ahead and hit it and hope! ( kinda like when I played Golf)

Thanks again PP

   Did not go the route of beveling, a little beyond my skill level at this point maybe next build I'll consider it. Going to focus on two things 1- clean finish for the cloth to lay and 2- consistent shape on the edge however sharp or not. 
I'll be painting and with a light color remembering my auto repair days a light color hides many sins you had to be really good to paint a car black after body repair.