two different approaches on the same problem

Let's presume your isp had the following config on your its side:

interface FastEthernet0/8
description Link to Dan - 1M
switchport access vlan 634
switchport trunk encapsulation dot1q
switchport trunk native vlan 635
switchport trunk allowed vlan 2,635
switchport mode trunk
no cdp enable
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
spanning-tree guard none
service-policy input dan-1024

Why is it trunk? Because in between this switch and myself there is a radio bridge which is currently using vlan2 (for monitoring purpose). All of the sudden this config stops working after an IOS upgrade (says my ISP). (I was accessing vlan 635 on my side : switchport access vlan 634).

Since it was unlikely for my ISP to solve the problem (i don't know exactly what was wrong, they did not know either), here's the two approaches i found for this:

I had a 1800router with a NM8-ESW card

1. moved the cable from the radio unit to the NM-8ESW interface, put one of the fast
interfaces (fe0/0/1) to trunk mode, created vlan 634 (corresponding to
my vlan in the isp network), and after this changed the source
interface for tunnel1 from fast0/1 to vlan634 (which i configured with
ip address x.y.z.6/30). Was working, but had to try the next thing as well (see 2.)

2. put the cable from the radio unit back to fast0/1 , created a subinterface
on this (fast0/1.1) , assigned x.y.z.6/30 and encapsulation dot1q
634. Working again. Moved tunnel source to fa0/1.1

My relevant config:

ip sla monitor 1
type echo protocol ipIcmpEcho z.g.h.3
frequency 5
ip sla monitor schedule 1 life forever start-time now
ip sla monitor 2
type echo protocol ipIcmpEcho h.k.l.2
frequency 5
ip sla monitor schedule 2 life forever start-time now

track 123 rtr 2 reachability

!
interface Tunnel1
description gre pri tunnel
bandwidth 1024
ip unnumbered Loopback0
ip hold-time eigrp 31 60
ip tcp adjust-mss 1300
delay 40000
keepalive 33 3
tunnel source FastEthernet0/1.1
tunnel destination z.g.h.3

interface FastEthernet0/1.1
description radio connection x.y.z.6 to isp
bandwidth 1024
ip address x.y.z.6 255.255.255.252
encapsulation dot1q 634

the other tunnel doesnt matter, my other link was working fine.

Why I posted this? Because I need some advice. The last version is the version I'm using now, but I would like a second opinion on the two versions I've posted. Or maybe some other solution. Thanks in advance.