One other suggestion that I might make is to go with a one piece IFS if you really want to go that direction. Something like the T232-2202-00 from Ziggs.
The alignment of all of the pieces in the front suspension is absolutely critical to safe operation and proper function. A one piece unit like that will be much easier to assemble and install.
Make sure you spend plenty of time with your welder practicing before you do any frame welding. Or better yet, get someone with experience/training to weld the IFS in. It is really easy to have a weld that looks fine, but does not penetrate and will fail at the most inopportune time.
If a weld on your bumper mount fails, it looks ugly and maybe you do some body damage. If a weld on your IFS fails, somebody could easily die. Don't take that risk.