It's good to plan ahead for the end toggles - a block of wood is lighter than an end pour. But , adding an end pour is common - just enough to do the job - set the boat on end and lower a 'little bucket' (paper cup with suspension) of epoxy into the end of the boat, then 'dump' it with a tripping line. Best not to add too much at once as the heat buildup can be a problem. Don't make the epoxy mix too thick - I'd use microballoons vs wood flour as thickener.
If you are going to use the through-hole, I recommend the NDK style with a single line toggle. No chance of trapping fingers in a loop.
View attachment 8594
I use a U-bolt epoxied through the deck into the end of the kayak. The stainless 'U' from a (saddle-type) wire cable clamp is a good small U-bolt.
On my current project I just bent a piece of stainless rod and epoxied that for the bow toggle and perimeter line attachment.
If you are using a U-bolt or a larger hole through the bow, IMO you should stitch the two lines together to prevent trapping hand/fingers.
View attachment 8595
That pic shows the U-bolt on the end of a Mariner; that bolt is a lot 'heftier' than I use in my builds.
For handles, PVC pipe works OK, but you can get very good and comfortable toggles from China (eBay) for a few dollars.
Here's the bow of my Frej kayak - smaller U-bolt from a cable clamp and Chinese toggle:
View attachment 8596