All the LA and FP engines appear to have the same size and dimension carb boss and usually interchange venturis.
The Fora F2D 15 needle valve assembly installs with a nut so the engines can pretty easily modified to fit. Use 118 angle drills if you can find them. Otherwise standard drills will work.
The fuel inlet side is under 1/4 in., so a single drill will do it. Clamp the block in a vice, preferably unassembled. Use an electric hand drill and take light cuts. Make sure the drill is square to the case. Go in until the needle valve hole is centered. That will leave about .050 material to hold the needle valve body in place.
On the needle side the nut is bigger, about .270. Start with a quarter inch drill and then finish off with the larger one. The nut will end up buried in the case with about .050 of material supporting it.
Stick the nut in the left side. Spin the needle valve body in until it starts to snug up. If the fuel feed is not in the right spot, sping it out, keeping one finger on the nut so it doesn't turn. Reposition the nut a flat or two at a time until the NV body ends up where you want it when snugged down.
Make a needle keeper from a short piece of tubing, 2mmX 5mm is about right, about 5-6mm long goes over the needle. It will squish and will keep the needle from turning after starting.
On a 25 the F2D valve has about 1/3-1/2 turn between rich and getting too lean on a high pressure bladder.
The assemblies are available from aerohobby.ca, and cheaper and more expensive prices are available from Yuvenko, Technohobby, and other European sources.